Although 80% of women in the United States experience vasomotor symptoms (VMS) during the menopausal transition the physiologic trigger mechanism is unknown. The Impaired Glucose Delivery Model proposes an innovative basis for vasomotor symptoms. This model emerged from animal studies exploring the neuroprotective aspects of estrogen. One such role of estrogen is to mediate transcription of mRNA for production of glucose transporters at the blood brain barrier (BBB). Glucose transport across the BBB is upregulated when blood glucose falls and down-regulated when blood glucose is elevated by changing transcription rates. At menopause, the hot flash may be triggered by a muted ability to up-regulate mRNA transcription when blood glucose declines resulting in decreased glucose transport. The proposed study will examine the relationship between VMS frequency and blood glucose under controlled conditions. The specific aims are to: a) determine if experimentally increasing the blood glucose level above 120 mg/dl reduces the frequency of VMS compared to the fasting condition in a diverse sample of symptomatic women; b) determine if either BMI or race/ethnicity are related to VMS frequency during normal saline infusion to maintain the fasting state; and c) determine if either BMI or ethnicity are related to VMS frequency during increased blood glucose conditions (treatment). A volunteer sample of 45 healthy, symptomatic postmenopausal women (age 45-60) will be recruited. The study will be conducted in one time series experimental period for each participant. While monitoring skin conductance for VMS, blood glucose level will be manipulated through sequential infusions of normal saline and glucose. The proposed study will provide critical information for the development of effective non-pharmacologic management strategies regulating blood glucose through diet and exercise. This study is designed to examine changes in blood sugar levels in the brain as a contributing factor in hot flashes at menopause. Using IV fluids, we will see if there is a difference in the number of hot flashes when we increase blood sugar levels and when blood sugar levels are kept low in a sample of women who have hot flashes. Our ultimate goal is to development hot flash treatment strategies aimed at keeping blood sugar at stable levels. [unreadable] [unreadable] [unreadable] [unreadable]